On the display screens of terminals such as smart phones and tablets, electronic books or the like are, for example, displayed. Accordingly, there have been developed technologies to perform selection operations and input operations on character strings displayed on screens based on the touch devices of terminals (see, for example, Japanese Patent Application Laid-open No. 2012-221367 and Japanese Patent Application Laid-open No. 2010-130214).
Generally, methods of controlling one or a plurality of characters to be selected are based on character selection methods provided by operating systems (hereinafter referred to as OSs). Specifically, users select object character strings among those displayed on screens by, for example, tracing or tapping the screens with fingers. Alternatively, the users input character strings using software keyboards installed in smart phones or the like. In this manner, input characters are controlled to be selected.
Patent Literature 1: Japanese Patent Application Laid-open No. 2012-221367
Patent Literature 2: Japanese Patent Application Laid-open No. 2010-130214